1. Field of the Invention
The present invention generally relates to controllable suspension systems for all terrain vehicles. More particularly, the present invention relates to controllable suspension systems wherein a plurality of springs are selectively enabled or disabled to alter an effective spring constants and the overall rigidity of the suspension systems.
2. Description of Related Art
All terrain vehicles are becoming a workhorse in a variety of applications. In addition, these same all terrain vehicles are often operated by one or more operators for recreational purposes. The ride of the vehicle is often configured for use in a single type of terrain. However, in use, the same vehicle may encounter both smooth and level terrain and rough and rocky terrain in short time intervals. As a result of such a compromised suspension system, the vehicle may handle poorly in one type of environment relative to the other.
Furthermore, the vehicle may encounter a variety of loading conditions depending upon the number of operators and the weight being hauled or towed by the vehicle. Again, the vehicle is often configured to have a certain type of ride based upon an average weight anticipated as being carried. The compromised solution may result in a overly stiff ride for light riders and an overly soft ride for heavier or multiple riders.
Moreover, as all terrain vehicles are typically operated in muddy environments, it is not uncommon for the vehicle itself to be covered with the mud encountered in the environment of use. Accordingly, vehicles having an adjustable spring assembly, such as those requiring appropriate pretensioning of the spring to alter handling characteristics, do not lend themselves to rapid changes in the field. Moreover, working on such systems may require the rider to dismount from the vehicle into wet or muddy operating conditions. The systems may only be accessible from below the vehicle or through tight access channels. Therefore, frequent adjustment of such suspension systems was neither desirable nor possible.
Also, systems having operators located within the rear fender were often covered with mud and debris thrown from the tires. Should the operator be covered with mud, altering the spring characteristics was likely fraught with difficulty and inconvenience. Moreover, as the working components of the spring characteristic adjusting mechanism were covered with mud, the mud and water may interfere with the operation of the mechanism itself. Accordingly, the adjustment mechanism became a maintenance nightmare and troublesome to operate.